Blasting wheel construction



June 29, 1965 H. s. CHAMBERS 3,191,346

BLASTING WHEEL CONSTRUCTION Q Filed Aug. 9, 1961 2 Sheets-Sheet 1 INVENTOR l ww lmw ATTOlNEY June 29, 1965 H. s. CHAMBERS BLASTING WHEEL CONSTRUCTION 2 Sheets-Sheet 2 Filed Aug. 9. 1961 INVENTOR M4 ATTORNEY United States Patent 3,191,346 BLASTING WHEEL CONSTRUCTION Howard S. Chambers, Chambersburg, Pa., assignor, by mesne assignments, to The Pangborn Corporation, Hagerstown, MIL, a corporation of Delaware Filed Aug. 9, 1961, Ser. No. 130,313 4 Claims. (Cl. 519) The present invention relates to blasting wheels of the type used to rapidly project a stream of particles against work pieces for the purpose of abrading, cleaning, peening or otherwise working said pieces. A wheel of this type is shown, for example, in U.S. Patent 2,869,289 granted January 20, 1959.

Among the objects of the present invention is to provide an improved blasting wheel construction which is more desirable to manufacture, use and maintain.

The above as well as additional objects of the present invention will be more clearly understood from the following description of several of its exemplifications, reference being made to the accompanying drawings wherein:

FIG. 1 is a sectional view of a blasting wheel construction in acordance with the present invention, the section being taken along the axis around which the wheel rotates; and

7 FIG. 2 is a sectional view of the construction of FIG. 1 taken along the line 22.

According to the present invention a blasting wheel assembly including a projecting wheel with outwardly extending propelling vanes, has a housing coveringthe wheel and guarding against the escape of blastant particles in any undesired direction, the interior of the housing being line with wear platestructure that is entirely supported by securing elements on the housing face of the wear plate structure and no securing elements are exposed to the projected particles.

The securing elements are preferably threaded members cast in place on the housing face of the wear plate structure, but they can also be in the form of cement adherently holding the wear plate against the housing Walls.

A very elfective form of wear plate for the above combination has a generally flat body portion shaped approximately as the segment of an annulus, with an arcuate rib protruding from the intermediate portion of one face and following the segmental form of the body, the body edge nearest the center of the annulus being tapered to a relatively thin line, and the body face opposite the ribbed face having two protruding spaced bosses each With a relatively soft steel nut locked in by casting, with the threaded portions of the nuts exposed for anchoring.

The wear plate of the present invention can also be used to help seal against leakageof blastant particles along the spindle upon which the wheel is journaled. Thus the wheel assembly having its spindle journaled in and. projecting out from one end of a tubular housing with its throwing Wheel secured to the projecting spindle end and its box housing around the wheel and fastened to the tubular housing, has a passageway in the box housing through which the spindlepene-trates.

' According to one aspect of the present invention, a sealing ring is clamped to the housing combination so as to encircle the spindle where it penetrates through the above passageway. A labyrinth sealing member is secured to the spindle and coacts with the sealing member to form a labyrinth seal that reduces the above leakage, and a gasket-type. joint is made between the sealing ring and the box housing to further limit such leakage. This gasket-type joint is conveniently made by cementing a ring of sponge rubber, for example, in a groove that extends around the outer surface of the sealing ring, and

3,191,346 Patented June 29, 1965 arranging the wear plate structure so that the edge of that structure tapers down to substantially a line and this edge is placed in compressive engagement with the rubber ring.

Another aspect of the present invention is the use of spindle bearings of the twin-row type with a lubricating connection from between the rows to a source of lubricant so that minimum amounts of fresh lubricant will keep each bearing row properly lubricated.

Turning now to the drawings, the apparatus of FIG. 1 shows a throwing wheel 20 having a spindle 30 rotatably mounted on suitable journals and carrying a runner head 32 upon which throwing vanes 34 are mounted. The spindle 30 is shown as provided at one end with an enlarged flange 36 to which the head 32 can be firmly secured as by means of bolts penetrating through the flange and runner head from either side. The runner head is desirably of relatively massive construction so that unsymmetrical erosion of the throwing vanes will not significantly unbalance the unit dynamically.

The vanes 34 can be held in place in any suitable manner such as shown in U.S. Patent 2,732,666 granted January 31, 1956.

In the opening 40 provided at the center of the runner head there is positioned a discharge directing feed for blastant particles. This feed per se forms no part of the present invention and is accordingly not illustrated. It can be of the types shown in U.S. Patent 2,732,666, or of any other construction.

A box-shaped housing 44 is shown in FIG. 1 as surrounding the Wheel 20 and is open at 46 to permit the blastant particles to be projected out from the wheel in the desired direction. The housing has a front wall 48, a rear wall 50, side walls 51, 52, and a cover 54, all of which cooperate to prevent the escape of blastant particles in any other direction. The walls and cover are protected by wear plates made of material that is very highly abrasion-resistant and are readily replaceable. These plates can also extend out through opening 46 so as to form an extension of the housing, as indicated at 56.

For the rear housing wall 50 the wear plate structure includes four separate wear plate segments 61, 62, 63 and 64, which fit together to form a generally annularlyshaped assembly surrounding the spindle 30. These segments have projecting from their exposed faces protruding arcuate rib sections .66, which together form a ring baifiethat extends close to the periphery of the runner head 32. This reduces the passage .of blastant particles into the place behind the runner head. The baffle ring can be provided with apertures :such as the tapered passageways 68 and can also have a gap 70 at its lowest portion to help drain or permit throwing out of those blastant particles which manage to find their way into the space within the bafile ring.

The rear wear plate segments are secured to the rear housing wall 50 in the illustrated construction by providing the segments with nuts 72 that are cast in place on the segment faces that engage the housing. Such nuts can be made of ordinary relatively soft steel such as SAElOlO or a hardened form of such relatively soft steel. Each segment is cast of the extremely hard wearresistant material and during the casting the nuts hold in appropriate position by means of threaded nut retainers or inserts that permit the cast metal to surround substantially the entire nut and leave essentially only its thread exposed. The insert itself blocks the cast metal from getting int-o the threaded portion of the nut and also leaves an access opening 74 through which the threaded portion can be reached. After the casting is completed, the nut retainers are unthreaded and Without any machining operations whatever, the segments can then be fitted in place.

3 A boss or pad 76 is provided around each nut so as to project away from the main portion of the housing-en'- gaging face of the segments, and these bosses are received in locating opening 73 in the housing wall. Bolts such as indicated at can then be threadedly engaged in the nuts to anchor the segments against the housing wall.

.Washers 82 fitted under the heads of the bolts enable the use of standard size, relatively small heads.

The front housing wall 48 can have wear plate segments made in exactly the same way but without the baffle rib. Both the front and the rear wear plate assemblies can also have at their lowest portions outwardly directed ribs 84 which help inreducing warpage during the casting.

The wear plates 88, 89 used to protect the end walls 51, 52' of the housing, can be perfectly flat structures resting on mounting clips 86 secured as by bolting to the outermost portions of the lower edges of segments 61, 64, and to the corresponding locations of the front wall wear plates.

The wear plate assembly is completed by a cap plate 9i) that is cast in arcuate form so as to rest on the arcuate tops of the front and rear wear plates. Also to provide lifting means, the cap plate 90 is fitted with lifting eyes 92. One very effective way to accomplish this is by having eyes E 2 made of standard eye-bolts having threaded shanks @4 and casting the shanks in place in bosses 96. Before casting, the thread on shanks 94 is deformed sufficiently to prevent the eyes from subsequently being unscrewed without damaging the threads so badly as to destroy the locking engagement this thread supplies with the metal cast around it. One simple way to deform the thread in this manner is to place the threaded eye-bolt on an anvil and strike the exposed thread with a sledge hammer or punch press.

The box-like housing 44 surrounding the Wheel 2t is secured as by bolting to a tubular housing Nil through which spindle 3% projects. Both of these housings are accordingly held as a unit and can consequently be mounted wherever the stream of blastant is to be applied, using a supporting plate for a common mounting member if desired. Twin row roller bearings 10 i and 195 journal the spindle in place in tubular housing Tilt), and are protected by labyrinth seals to minimize the danger of fine particles working their way into the bearings. Bearing 104 is particularly susceptible to such damage because of the fairly direct communication from this bearing to the interior of the housing 44 through the opening 45 provided in the rear housing wall for passage of the spindle 30 as well as its flange 36.

In the illustrated construction a first labyrinth seal for bearing 104 is provided by a generally cylindrical collar encircling the spindle and secured in position by an outwardly projecting flange 112 which is bolted to the tubular housing. The internal face of the collar 110 can have a number of grooves 114 spaced longitudinally from each other, and is positioned very closely around a sleeve 116 which is secured to the spindle. A central outwardly projecting rib 118 on the sleeve provides a socket 120 through which one or two set screws can be threaded and brought into tight fitting engagement with the spindle, or with the floor of a groove 122 appropriately located on it.

Rib 118 is also brought into close spacial relation with the forward edge 124 of collar 110, and this edge can be extended radially to improve the sealing action. The

rib also overhangs the outer face 126 of this edge of the collar 110 as a still further improvement.

An additional seal for bearing 1M is'provided by a sealing ring 130 which has a generally U-shaped wall section. One arm 131 of the U is made longer than the other and is shaped so as to be clamped between the tubular housing 1% and the box housing 44. The other arm 132 of the U is fitted very closely adjacent the periphery of spindle flange 36. An additional ring 134 is secured to the spindle flange 36 as by pressing around it,

2. and projects rearwardly sufficiently far to form a labyrinthine passageway 136 with arm 132.

In the above arrangement any particles that tend to reach the outwardly facing surface of ring 13f from the interior of the housing, will have to go through the labyrinthine passageway 13% before they reach the space 14% around the spindle where it passes through the box housing. This space 140 is of annular shape encircling the spindle but in its lowest portion it is open to the outside so that particles can drop out here. Another opening 14 3 can also be provided in the inner end of tubular housing 1594) so that space Mil has anothercommunication path to the outside.

A barrier against still further influx of particles into space 14% is established by a gasket-type seal between ring llil and the housing 44. A ringshaped gasket such as one made of sponge rubber 148, can be cemented in a groove around the ring 13(i'and into this gasket ring is pressed the circular inner edge of the rear wear plate assembly. For best sealing, this inner edge is tapered to a line g To allow good pressing action, the openings in the rear housing wall 5@ in which the nut-carrying bosses 76 are received, are made oversize. The rear wear plate segments can then be loosely secured by their fastening bolts 86, after which the plates can be slid into the desired engagement with the gasket ring and the bolts then tightened.

As an additional and very helpful protection for heatings 1M and W5, they are provided with a set of lubrication passageways 152 between the two rows of bearing rollers. These passageways 152 cooperate with a peripheral groove 1% and a supply passageway 156 in housing 1% to direct lubricant between the rows of bearings. The introduction of fresh lubricant will accordingly move old lubricant out towards the labyrinth seals and thereby assure most effective lubrication by flushing out any particles that happen to get as far as the lubricant and are there trapped. A grease fitting 158 permits convenient lubrication with every lubricating treatment giving the most eficient cleaning ofboth rows of bearings. A similar lubrication arrangement is provided for bearing Hi5 although in this location the bearing is not as vulnerable, and a labyrinth such as indicated will usually sutfice with any type of lubrication.

The use of unbroken surfaces on the wear plates is very beneficial. Not only does this make it unnecessary to have expensive highly hardened fasteners otherwise needed because they are exposed to an intense blasting action, but in addition fine blastant particles readily penetrate into the thread of threaded fasteners exposed to the wheel, and tend to jam these threads. Furthermore in place of the countersunk flat head screws inserted from the interior of the housing as used in some of the most effective prior art constructions, the fasteners of the present invention are inserted from the outside of the housing and are therefore much more convenient to manipulate. Moreover the accessibility made possible by receiving the fastener bosses in housing openings, substantially completely avoids the groping otherwise needed to thread fasteners into heavy members that cannot be held by the same person doing the threading because of the intervening housing wall.

According to the present invention the wear members can be secured in place by cementing rather than bolting. This eliminates the fastening bolts and nuts, but thepositioning bosses can be retained since they help position the plates for cementing and also help support the plates, thereby requiring less cement bond. The mounting bosses can also be eliminated if the cement bond is adequate to rely upon- Although any type of cement suitable for use with metal is effective, the preferred cements are of thermoplastic nature since plates cemented with these cements are readily removed by merely melting the cement.

Shellac, polyamide resins such as nylon66 and vinyl acetal resins fall in this category and give satisfactory results. Polyvinyl acetate and polyvinyl alcohol-acetate as well as polyvinyl chloride and polyvinyl propionate are other resins that are suitable.

The wear plates can also be held by merely interlocking them with each other and with suitable openings or other engagement surfaces in the housing. Thus by fitting the end plates and cap plate between the front and back plate assemblies, the front and back assemblies will be locked in place with their positioning bosses 76 held in their receiving openings in the housing walls. The segments of the front and/ or back plate assemblies can be partially or completely combined in integral form to better assure such locking.

To secure the end plates, the front and back plates can have their side margins extended and curved inwardly so that they form a channel in which the end plates must he slid for mounting or removal. The top plate is conveniently held in place against the other wear plates by the top of the housing.

Obviously many modifications and variations of the present invention are possible in the light of the abdve teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed:

1. A wear plate for a blasting wheel housing, said plate having a smooth unbroken imperforate inner face and a generally flat body shaped approximately as the segment of an annulus, said body having an inner edge and an outer edge with an intermediate portion between said edges, said inner edge being nearer to the center of the annulus than said outer edge, an arcuate rib protruding from the intermediate portion of one face and following the segmental form of said body, said inner edge being tapered to a relatively thin line, and the body face opposite the ribbed face having a plurality of protruding spaced bosses each with a relatively soft steel nut locked in by casting, said nuts having threaded portions exposed for anchoring.

2. A blasting wheel assembly for projecting a stream of lastant particles at work articles, said assembly including a projecting wheel with outwardly extending propelling vanes, a walled housing covering said wheel for guarding against the escape of particles in any undesired direction, wear plates lining said walled housing, each of said wear plates having a housing face disposed toward said housing and an interior face disposed toward said wheel, said interior face being smooth and imperforate, spaced bosses on said housing face of each of said wear plates projecting through said walled housing and having cast in place nuts therein, and threaded fasteners secured to each of said nuts and to said walled housing.

3. The combination of claim 2 wherein the wear plate for the rear wall of said housing is in segmental form with individual segments positioned for slidable adjustment in the housing.

4. The combination of claim 2 wherein one of said wear plates is shaped approximately as the segment of an annulus, said segmental shaped wear plate having an inner edge and an outer edge with an intermediate portion between said edges, said inner edge being nearer to the center of the annulus than said outer edge, an arcuate rib protruding from said intermediate portion of said smooth surface and following the segmental form of said annulus, and said inner edge of said annulus being tapered to a relatively thin line.

References Cited by the Examiner UNITED STATES PATENTS 821,297 5/06 Kohler 1514l.71

856,246 6/07 Gamon 15141.71 1,259,224 3/ 18 Guibert 22-203 1,591,938 7/26 Harrison. 1,601,956 10/ 26 Gamrneter. 2,058,257 10/36 Porteous 51-164 X 2,108,005 2/ 38 Keefer 51-9 2,108,211 2/ 38 Rosenberger 51-9 2,341,559 2/44 Keefer 51-9 2,442,678 6/48 Dybiec 51-9 2,605,148 7/52 Shoup 308-187 2,653,064 9/53 Heim 308-187 2,732,666 1/56 Powell 51-9 2,819,562 1/58 Barnes 51-9 2,855,250 10/58 Peycke 308-187 2,861,617 11/58 Tinnerman l5l-41.73 2,869,289 l/ 59 Gossard 51-9 2,909,870 10/59 Barnes 51-9 2,975,865 3/61 Rumpel 308-187 X 3,112,540 12/ 63 Kaneko et al 22-203 LESTER M. SW INGLE, Primary Examiner.

JOHN C. CHRISTIE, FRANK H. BRONAUGH,

J. SPENCER OVERHOLSER, Examiners. 

2. A BLASTING WHEEL ASSEMBLY FOR PROJECTING A STREAM OF BLASTANT PARTICLES AT WORK ARTICLES, SAID ASSEMBLY INCLUDING A PROJECTING WHEEL WITH OUTWARDLY EXTENDING PROPELLING VANES, A WALLED HOUSING COVERING SAID WHEEL FOR GUARDING AGAINST THE ESCAPE OF PARTICLES IN ANY UNDESIRED DIRECTION, WEAR PLATES LINING SAID WALLED HOUSING, EACH OF SAID WEAR PLATES HAVING A HOUSING FACE DISPOSED TOWARD SAID HOUSING AND AN INTERIOR FACE DISPOSED TOWARD SAID WHEEL, SAID INTERIOR FACE BEING SMOOTH AND IMPERFORATE, SPACED BOSSES ON SAID HOUSING FACE OF EACH OF SAID WEAR PLATES PROJECTING THROUGH SAID WALLED HOUSING AND HAVING CAST IN PLACE NUTS THEREIN, AND THREADED FASTENERS SECURED TO EACH OF SAID NUTS AND TO SAID WALLED HOUSING. 